Post-Vaccination SARS-CoV-2 IgG Antibody Titres in Retinal Vein Occlusion Patients: A Cross-Sectional Analysis

Purpose: The objective of the present study is to examine the levels of SARS-CoV-2 IgG antibody titres post COVID-19 vaccine in retinal vein occlusion (RVO) patients and in healthy control group; study conducted at the Regional Institute of Ophthalmology, Pt. B.D. Sharma PGIMS, Rohtak (Haryana), India. Methods: This study enrolled 215 patients with a confirmed diagnosis of retinal vein occlusion (RVO) based on comprehensive ophthalmic evaluation, including slit-lamp biomicroscopy, fundus examination, optical coherence tomography and fluorescence angiography. At presentation, all patients presented with sudden painless diminution of vision in affected eye with no other signs of recent SARS-CoV-2 infection. Patients with preexisting Type 2 Diabetes Mellitus, hypertension and old vascular occlusion were excluded. A control group of 100 age-matched healthy individuals was also included. Clinical variables such as sex distribution, best-corrected visual acuity, fundus characteristics, temporal profile of RVO onset, and history of COVID-19 infection and hospitalisation as well as details of COVID-19 vaccination were documented. Quantitative estimation of SARS-CoV-2 antibody titres (IgG and IgM) in both cases and controls was performed using a standardized enzyme-linked immunosorbent assay (ELISA). Results: The mean SARS-CoV-2 IgG antibody titres in the RVO group who have received two COVID-19 vaccines (190.80 ± 20.06 pg/nm) was significantly higher than in the control group (111.45 ± 18.61 pg/nm), indicating a potential association between post COVID -19 vaccination elevated IgG antibody titres in RVO patients (p < 0.001). IgM levels were negative in both groups. All enrolled patients as well as controls were vaccinated with 2 doses of ChAdOx1 n CoV- 19 Corona Virus Vaccine, named as COVISHIELD ; It is a recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 Spike (S) glycoprotein. There was no significant history of COVID-19 infection as well as hospitalisation in both groups. The mean duration between two vaccine dose was 4-6 weeks , all participants included in study have received last vaccine before 6-7 months of study. The low standard errors (2.40 for controls, 1.37 for RVO) suggest consistency within each group, and the bar chart illustrates the marked elevation in IgG titres levels among RVO patients. However, no significant association was observed between age and COVID-19 antibody titres in RVO patients, nor between antibody titres and sex. Conclusion: This study demonstrates a strong correlation of post COVID- 19 vaccines related elevation of SARS-CoV-2 IgG antibody titres and retinal vein occlusion in our cohort, representing the first report of such an association from India.